Here are the sentences with the blanks filled, based on the provided context. Please note the answers might vary:
5. We are in Madrid.
6. My sister and brother are ten.
7. You are not a student.
8. Is he Nick or Mark?
9. Are you ten or eleven?
10. Rex is funny.
Explanation:
* The verb 'to be' is filled in each sentence, taking into account the subject.
* The last sentences are filled with the verb to be in a form that creates a question (is, are) or complete a statement (is).